diff --git a/pkg/vm_service/.gitignore b/pkg/vm_service/.gitignore
index 113d7832bbe..2316a7c43a0 100644
--- a/pkg/vm_service/.gitignore
+++ b/pkg/vm_service/.gitignore
@@ -2,3 +2,7 @@
 .dart_tool
 .packages
 pubspec.lock
+
+java/build/
+java/dist/
+java/out/
diff --git a/pkg/vm_service/java/.gitignore b/pkg/vm_service/java/.gitignore
index d5685675be5..4fef6d53682 100644
--- a/pkg/vm_service/java/.gitignore
+++ b/pkg/vm_service/java/.gitignore
@@ -1,4 +1,100 @@
-build/
-dist/
-out/
-src/gen/
+# This is a generated file.
+
+src/org/dartlang/vm/service/VmService.java
+src/org/dartlang/vm/service/consumer/AllocationProfileConsumer.java
+src/org/dartlang/vm/service/consumer/BreakpointConsumer.java
+src/org/dartlang/vm/service/consumer/EvaluateConsumer.java
+src/org/dartlang/vm/service/consumer/EvaluateInFrameConsumer.java
+src/org/dartlang/vm/service/consumer/FlagListConsumer.java
+src/org/dartlang/vm/service/consumer/GetInboundReferencesConsumer.java
+src/org/dartlang/vm/service/consumer/GetIsolateConsumer.java
+src/org/dartlang/vm/service/consumer/GetMemoryUsageConsumer.java
+src/org/dartlang/vm/service/consumer/GetObjectConsumer.java
+src/org/dartlang/vm/service/consumer/InstanceSetConsumer.java
+src/org/dartlang/vm/service/consumer/InvokeConsumer.java
+src/org/dartlang/vm/service/consumer/ReloadReportConsumer.java
+src/org/dartlang/vm/service/consumer/RetainingPathConsumer.java
+src/org/dartlang/vm/service/consumer/ScriptListConsumer.java
+src/org/dartlang/vm/service/consumer/SourceReportConsumer.java
+src/org/dartlang/vm/service/consumer/StackConsumer.java
+src/org/dartlang/vm/service/consumer/SuccessConsumer.java
+src/org/dartlang/vm/service/consumer/TimelineConsumer.java
+src/org/dartlang/vm/service/consumer/TimelineFlagsConsumer.java
+src/org/dartlang/vm/service/consumer/TimestampConsumer.java
+src/org/dartlang/vm/service/consumer/VMConsumer.java
+src/org/dartlang/vm/service/consumer/VersionConsumer.java
+src/org/dartlang/vm/service/element/AllocationProfile.java
+src/org/dartlang/vm/service/element/BoundField.java
+src/org/dartlang/vm/service/element/BoundVariable.java
+src/org/dartlang/vm/service/element/Breakpoint.java
+src/org/dartlang/vm/service/element/ClassHeapStats.java
+src/org/dartlang/vm/service/element/ClassList.java
+src/org/dartlang/vm/service/element/ClassObj.java
+src/org/dartlang/vm/service/element/ClassRef.java
+src/org/dartlang/vm/service/element/Code.java
+src/org/dartlang/vm/service/element/CodeKind.java
+src/org/dartlang/vm/service/element/CodeRef.java
+src/org/dartlang/vm/service/element/Context.java
+src/org/dartlang/vm/service/element/ContextElement.java
+src/org/dartlang/vm/service/element/ContextRef.java
+src/org/dartlang/vm/service/element/ErrorKind.java
+src/org/dartlang/vm/service/element/ErrorObj.java
+src/org/dartlang/vm/service/element/ErrorRef.java
+src/org/dartlang/vm/service/element/Event.java
+src/org/dartlang/vm/service/element/EventKind.java
+src/org/dartlang/vm/service/element/ExceptionPauseMode.java
+src/org/dartlang/vm/service/element/ExtensionData.java
+src/org/dartlang/vm/service/element/Field.java
+src/org/dartlang/vm/service/element/FieldRef.java
+src/org/dartlang/vm/service/element/Flag.java
+src/org/dartlang/vm/service/element/FlagList.java
+src/org/dartlang/vm/service/element/Frame.java
+src/org/dartlang/vm/service/element/FrameKind.java
+src/org/dartlang/vm/service/element/Func.java
+src/org/dartlang/vm/service/element/FuncRef.java
+src/org/dartlang/vm/service/element/InboundReference.java
+src/org/dartlang/vm/service/element/InboundReferences.java
+src/org/dartlang/vm/service/element/Instance.java
+src/org/dartlang/vm/service/element/InstanceKind.java
+src/org/dartlang/vm/service/element/InstanceRef.java
+src/org/dartlang/vm/service/element/InstanceSet.java
+src/org/dartlang/vm/service/element/Isolate.java
+src/org/dartlang/vm/service/element/IsolateRef.java
+src/org/dartlang/vm/service/element/Library.java
+src/org/dartlang/vm/service/element/LibraryDependency.java
+src/org/dartlang/vm/service/element/LibraryRef.java
+src/org/dartlang/vm/service/element/LogRecord.java
+src/org/dartlang/vm/service/element/MapAssociation.java
+src/org/dartlang/vm/service/element/MemoryUsage.java
+src/org/dartlang/vm/service/element/Message.java
+src/org/dartlang/vm/service/element/Null.java
+src/org/dartlang/vm/service/element/NullRef.java
+src/org/dartlang/vm/service/element/Obj.java
+src/org/dartlang/vm/service/element/ObjRef.java
+src/org/dartlang/vm/service/element/ReloadReport.java
+src/org/dartlang/vm/service/element/Response.java
+src/org/dartlang/vm/service/element/RetainingObject.java
+src/org/dartlang/vm/service/element/RetainingPath.java
+src/org/dartlang/vm/service/element/Script.java
+src/org/dartlang/vm/service/element/ScriptList.java
+src/org/dartlang/vm/service/element/ScriptRef.java
+src/org/dartlang/vm/service/element/Sentinel.java
+src/org/dartlang/vm/service/element/SentinelKind.java
+src/org/dartlang/vm/service/element/SourceLocation.java
+src/org/dartlang/vm/service/element/SourceReport.java
+src/org/dartlang/vm/service/element/SourceReportCoverage.java
+src/org/dartlang/vm/service/element/SourceReportKind.java
+src/org/dartlang/vm/service/element/SourceReportRange.java
+src/org/dartlang/vm/service/element/Stack.java
+src/org/dartlang/vm/service/element/StepOption.java
+src/org/dartlang/vm/service/element/Success.java
+src/org/dartlang/vm/service/element/Timeline.java
+src/org/dartlang/vm/service/element/TimelineEvent.java
+src/org/dartlang/vm/service/element/TimelineFlags.java
+src/org/dartlang/vm/service/element/Timestamp.java
+src/org/dartlang/vm/service/element/TypeArguments.java
+src/org/dartlang/vm/service/element/TypeArgumentsRef.java
+src/org/dartlang/vm/service/element/UnresolvedSourceLocation.java
+src/org/dartlang/vm/service/element/VM.java
+src/org/dartlang/vm/service/element/VMRef.java
+src/org/dartlang/vm/service/element/Version.java
diff --git a/pkg/vm_service/java/version.properties b/pkg/vm_service/java/version.properties
index 68164e76d18..3360053feec 100644
--- a/pkg/vm_service/java/version.properties
+++ b/pkg/vm_service/java/version.properties
@@ -1 +1 @@
-version=3.23
+version=3.25
diff --git a/pkg/vm_service/tool/generate.dart b/pkg/vm_service/tool/generate.dart
index 5ff5c7dfcb8..151814fc776 100644
--- a/pkg/vm_service/tool/generate.dart
+++ b/pkg/vm_service/tool/generate.dart
@@ -17,20 +17,11 @@ final bool _stampPubspecVersion = false;
 /// Parse the 'service.md' into a model and generate both Dart and Java
 /// libraries.
 main(List<String> args) async {
-  bool generateJava = false;
-  if (args.length != 0) {
-    if ((args.length == 1) && (args.first == '--generate-java')) {
-      generateJava = true;
-    } else {
-      print('Invalid options: $args. Usage: dart generate [--generate-java].');
-      return;
-    }
-  }
   String appDirPath = dirname(Platform.script.toFilePath());
 
   // Parse service.md into a model.
-  var file =
-      new File(join(appDirPath, '../../../runtime/vm/service/service.md'));
+  var file = new File(
+      normalize(join(appDirPath, '../../../runtime/vm/service/service.md')));
   var document = new Document();
   StringBuffer buf = new StringBuffer(file.readAsStringSync());
   var nodes = document.parseLines(buf.toString().split('\n'));
@@ -38,15 +29,14 @@ main(List<String> args) async {
   print('Service protocol version ${ApiParseUtil.parseVersionString(nodes)}.');
 
   // Generate code from the model.
+  print('');
+
   await _generateDart(appDirPath, nodes);
-  if (generateJava) {
-    await _generateJava(appDirPath, nodes);
-  }
+  await _generateJava(appDirPath, nodes);
   await _generateAsserts(appDirPath, nodes);
 }
 
 _generateDart(String appDirPath, List<Node> nodes) async {
-  print('');
   var outDirPath = normalize(join(appDirPath, '..', 'lib'));
   var outDir = new Directory(outDirPath);
   if (!outDir.existsSync()) outDir.createSync(recursive: true);
@@ -71,14 +61,26 @@ _generateDart(String appDirPath, List<Node> nodes) async {
 }
 
 _generateJava(String appDirPath, List<Node> nodes) async {
-  print('');
-  var srcDirPath = normalize(join(appDirPath, '..', 'java', 'src', 'gen'));
-  assert(new Directory(srcDirPath).existsSync());
+  var srcDirPath = normalize(join(appDirPath, '..', 'java', 'src'));
   var generator = new java.JavaGenerator(srcDirPath);
   java.api = new java.Api();
   java.api.parse(nodes);
   java.api.generate(generator);
 
+  // We generate files into the java/src/ folder; ensure the generated files
+  // aren't committed to git (but manually maintained files in the same
+  // directory are).
+  List<String> generatedPaths = generator.allWrittenFiles
+      .map((path) => relative(path, from: 'java'))
+      .toList();
+  generatedPaths.sort();
+  File gitignoreFile = new File(join(appDirPath, '..', 'java', '.gitignore'));
+  gitignoreFile.writeAsStringSync('''
+# This is a generated file.
+
+${generatedPaths.join('\n')}
+''');
+
   // Generate a version file.
   Version version = ApiParseUtil.parseVersionSemVer(nodes);
   File file = new File(join('java', 'version.properties'));
@@ -88,7 +90,6 @@ _generateJava(String appDirPath, List<Node> nodes) async {
 }
 
 _generateAsserts(String appDirPath, List<Node> nodes) async {
-  print('');
   var outDirPath = normalize(join(appDirPath, '..', 'example'));
   var outDir = new Directory(outDirPath);
   if (!outDir.existsSync()) outDir.createSync(recursive: true);
diff --git a/pkg/vm_service/tool/java/src_gen_java.dart b/pkg/vm_service/tool/java/src_gen_java.dart
index 8c8e5d1a187..2e298a62023 100644
--- a/pkg/vm_service/tool/java/src_gen_java.dart
+++ b/pkg/vm_service/tool/java/src_gen_java.dart
@@ -50,8 +50,12 @@ class JavaGenerator {
   /// The java source directory into which files are generated.
   final String srcDirPath;
 
+  Set<String> _generatedPaths = new Set();
+
   JavaGenerator(this.srcDirPath);
 
+  Iterable<String> get allWrittenFiles => _generatedPaths;
+
   /// Generate a Java class/interface in the given package
   void writeType(String typeName, WriteType write) {
     var classWriter = new TypeWriter(typeName);
@@ -61,6 +65,7 @@ class JavaGenerator {
     if (!pkgDir.existsSync()) pkgDir.createSync(recursive: true);
     var classFilePath = join(pkgDirPath, '${classNameFor(typeName)}.java');
     var classFile = new File(classFilePath);
+    _generatedPaths.add(classFilePath);
     classFile.writeAsStringSync(classWriter.toSource());
   }
 }